RESDECs induce and form vessels in Matrigel plug. (A) RESDECs were imbedded in a permeable sponge (arrow) that was suspended in Matrigel and implanted subcutaneously. After 28 days, the mouse was injected intravenously with FITC-dextran and the Matrigel plug was removed and imaged to demonstrate neovascularization centered toward the RESDEC sponge. Original magnification, × 10. (B) RESDEC cells were uniformly resuspended in a Matrigel plug and implanted subcutaneously. After 32 days, FITC-dextran was injected intravenously and the plug was removed and imaged to demonstrate intact vessels formed from the RESDEC cells in the plug. Original magnification, × 40. (C-F) IHC demonstrates vessels in Matrigel plug (B) are RESDEC derived. Panels C, E, and G are phase contrast images of cross-sectioned Matrigel with RESDEC-derived vessels, and panels D, F, and H are corresponding fluorescent IHC images using either isotype control (IgG2a) antibody (D) or anti–HLA class I antibody, followed by secondary FITC-labeled antibody (F,H). Original magnifications: × 200 (C-D); and ×400 (E-H).